Microelectronic assemblies having magnetic core inductors

ABSTRACT

Microelectronic assemblies, related devices and methods, are disclosed herein. In some embodiments, a microelectronic assembly may include a first die having a first surface and an opposing second surface, wherein the first die is in a first dielectric layer; a magnetic core inductor, having a first surface and an opposing second surface, in the first dielectric layer, wherein the magnetic core inductor may include a first conductive pillar at least partially surrounded by a magnetic material, and a second conductive pillar coupled to the first conductive pillar; and a second die having a first surface and an opposing second surface, wherein the second die is in a second dielectric layer, and wherein the first surface of the second die is coupled to the second surface of the magnetic core inductor.

BACKGROUND

Integrated circuit (IC) packages may include integrated voltage regulators (IVRs) for managing power delivery to IC dies. Some IVRs may include magnetic core inductor structures.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments are illustrated by way of example, not by way of limitation, in the figures of the accompanying drawings.

FIG. 1A is a side, cross-sectional view of an example microelectronic assembly, in accordance with various embodiments.

FIGS. 1B-1C are magnified portions of FIG. 1A, in accordance with various embodiments.

FIG. 2A is a side, cross-sectional view of an example microelectronic assembly, in accordance with various embodiments.

FIGS. 2B-2C are top view schematics showing an integrated magnetic core inductor in the microelectronic assembly of FIG. 2A, in accordance with various embodiments.

FIG. 3A is a side, cross-sectional view of an example microelectronic assembly, in accordance with various embodiments.

FIG. 3B is a top view schematic showing an integrated magnetic core inductor in the microelectronic assembly of FIG. 3A, in accordance with various embodiments.

FIGS. 4A-4B are side, cross-sectional views of example microelectronic assemblies, in accordance with various embodiments.

FIGS. 5A-5G are side, cross-sectional views of various stages in an example process for manufacturing the microelectronic assembly of FIG. 1, in accordance with various embodiments.

FIGS. 6A-6B are side, cross-sectional views of example microelectronic assemblies, in accordance with various embodiments.

FIG. 7A is a top view schematic of an example transformer, in accordance with various embodiments.

FIG. 7B are side, cross-sectional schematics of the example transformer of FIG. 7A, in accordance with various embodiments.

FIG. 8 is a top view of a wafer and dies that may be included in a microelectronic assembly, in accordance with any of the embodiments disclosed herein.

FIG. 9 is a cross-sectional side view of an IC device that may be included in a microelectronic assembly, in accordance with any of the embodiments disclosed herein.

FIG. 10 is a cross-sectional side view of an IC device assembly that may include a microelectronic assembly, in accordance with any of the embodiments disclosed herein.

FIG. 11 is a block diagram of an example electrical device that may include a microelectronic assembly, in accordance with any of the embodiments disclosed herein.

DETAILED DESCRIPTION

Microelectronic assemblies, and related devices and methods, are disclosed herein. For example, in some embodiments, a microelectronic assembly may include a first die having a first surface and an opposing second surface, wherein the first die is in a first dielectric layer; a magnetic core inductor, having a first surface and an opposing second surface, in the first dielectric layer, wherein the magnetic core inductor may include a first conductive pillar at least partially surrounded by a magnetic material, and a second conductive pillar coupled to the first conductive pillar; and a second die having a first surface and an opposing second surface, wherein the second die is in a second dielectric layer, and wherein the first surface of the second die is coupled to the second surface of the magnetic core inductor.

Communicating large numbers of signals between two or more dies in a multi-die IC package is challenging due to the increasingly small size of such dies, thermal constraints, and power delivery constraints, among others. Various ones of the embodiments disclosed herein may help achieve reliable attachment of multiple IC dies at a lower cost, with improved power efficiency, with higher bandwidth, and/or with greater design flexibility, relative to conventional approaches. Conventional approaches may reduce signal crosstalk, signal coupling, and insertion loss by increasing the ratio of ground connections to signal connections, which is likely to lower the bandwidth density, increase the die area, and add latency due to the increased signal distance. Various ones of the microelectronic assemblies disclosed herein may exhibit better power delivery and signal speed while reducing the size of the package relative to conventional approaches. The microelectronic assemblies disclosed herein may be particularly advantageous for small and low-profile applications in computers, tablets, industrial robots, and consumer electronics (e.g., wearable devices).

In the following detailed description, reference is made to the accompanying drawings that form a part hereof wherein like numerals designate like parts throughout, and in which is shown, by way of illustration, embodiments that may be practiced. It is to be understood that other embodiments may be utilized, and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense.

Various operations may be described as multiple discrete actions or operations in turn, in a manner that is most helpful in understanding the claimed subject matter. However, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations may not be performed in the order of presentation. Operations described may be performed in a different order from the described embodiment. Various additional operations may be performed, and/or described operations may be omitted in additional embodiments.

For the purposes of the present disclosure, the phrase “A and/or B” means (A), (B), or (A and B). For the purposes of the present disclosure, the phrase “A, B, and/or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). The drawings are not necessarily to scale. Although many of the drawings illustrate rectilinear structures with flat walls and right-angle corners, this is simply for ease of illustration, and actual devices made using these techniques will exhibit rounded corners, surface roughness, and other features.

The description uses the phrases “in an embodiment” or “in embodiments,” which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments of the present disclosure, are synonymous. As used herein, a “package” and an “IC package” are synonymous, as are a “die” and an “IC die.” The terms “top” and “bottom” may be used herein to explain various features of the drawings, but these terms are simply for ease of discussion, and do not imply a desired or required orientation. As used herein, the term “insulating” means “electrically insulating,” unless otherwise specified. Throughout the specification, and in the claims, the term “coupled” means a direct or indirect connection, such as a direct electrical, mechanical, or magnetic connection between the things that are connected or an indirect connection, through one or more passive or active intermediary devices. The meaning of “a,” “an,” and “the” include plural references. The meaning of “in” includes “in” and “on.”

When used to describe a range of dimensions, the phrase “between X and V” represents a range that includes X and Y. For convenience, the phrase “FIG. 4” may be used to refer to the collection of drawings of FIGS. 4A-4B, the phrase “FIG. 5” may be used to refer to the collection of drawings of FIGS. 5A-5G, etc. Although certain elements may be referred to in the singular herein, such elements may include multiple sub-elements. For example, “an insulating material” may include one or more insulating materials. As used herein, a “conductive contact” may refer to a portion of conductive material (e.g., metal) serving as an electrical interface between different components; conductive contacts may be recessed in, flush with, or extending away from a surface of a component, and may take any suitable form (e.g., a conductive pad or socket, or portion of a conductive line or via).

FIG. 1A is a side, cross-sectional view of a microelectronic assembly 100, in accordance with various embodiments. The microelectronic assembly 100 may include a package substrate 102 coupled to a multi-layer die subassembly 104 having integrated magnetic core inductors (“MCI”) 190A, 190B.

FIGS. 16-1C are magnified portions of FIG. 1A, in accordance with various embodiments. In particular, as shown in FIG. 1B, the MCI 190A may include a first conductive pillar 192-B1 surrounded by a magnetic material 194 and a second conductive pillar 192-B2. The MCI 190A may have a first surface 170-1 and a second surface 170-2. The first conductive pillar 192-B1 may be electrically coupled via a conductive pathway 196A in the package substrate 102 to the second conductive pillar 192-B2 at a first or bottom end (e.g., at the first surface 170-1), and the first and second conductive pillars 192-B1, 192-B2 may be electrically coupled to a die 114-3 at a second or top end (e.g., at the second surface 170-2). In some embodiments, the first and second conductive pillars 192-B1, 192-B2 both may be surrounded by a magnetic material 194. In some embodiments, the first and second conductive pillars 192-B1, 192-B2 may be electrically coupled via a conductive pathway in the multi-layer die subassembly 104.

As shown in FIG. 1C, the MCI 190B may include four conductive pillars, a first conductive pillar 192-C1, a second conductive pillar 192-C2, a third conductive pillar 192-C3, and a fourth conductive pillar 192-C4. The MCI 190B may have a first surface 170-1 and a second surface 170-2. The first conductive pillar may be surrounded by a magnetic material 194. Although FIG. 1C shows a single conductive pillar surrounded in magnetic material, one or more conductive pillars (e.g., any number of the conductive pillars) may be surrounded in magnetic material, for example, two or more conductive pillars may be surrounded in conductive material. As shown in FIG. 1C, the first conductive pillar 192-C1 may be electrically coupled to the second conductive pillar 192-C2 at a first end (e.g., at the first surface 170-1) via a conductive pathway 196B in the package substrate 102, the second conductive pillar 192-C2 may be electrically coupled to the third conductive pillar 192-C3 at a second end (e.g., at the second surface 170-2) via a conductive pathway 196C in the multi-layer die subassembly 104, and the third conductive pillar 192-C3 may be electrically coupled to the fourth conductive pillar 192-C4 at a first end (e.g., at the first surface 170-1) via a conductive pathway 196D in the package substrate 102. In some embodiments, the conductive pathways 196B, 196D at the first end (e.g., at the first surface 170-1) may be electrically coupled via a conductive pathway in the multi-layer die subassembly 104.

The multi-layer die subassembly 104 may include multiple interconnects. As used herein, the term a “multi-layer die subassembly” 104 may refer to a composite die having two or more stacked dielectric layers with one or more dies in each layer, and conductive interconnects and/or conductive pathways connecting the one or more dies, including dies in non-adjacent layers. As used herein, the terms a “multi-layer die subassembly” and a “composite die” may be used interchangeably. As used herein, the term “multi-level interconnect” 152 may refer to an interconnect that includes a conductive pillar between a first component and a second component where the first component and the second component are not in adjacent layers, or may refer to an interconnect that spans one or more layers (e.g., an interconnect between a first die in a first layer and a second die in a third layer, or an interconnect between a package substrate and a die in a second layer). As shown in FIG. 1, the multi-layer die subassembly 104 may include two layers. In particular, the multi-layer die subassembly 104 may include a first layer 104-1 having a die 114-2, and a second layer 104-2 having a die 114-3, a die 114-5, and a die 114-6. The die 114-2 in the first layer 104-1 may be coupled to the package substrate 102 by die-to-package substrate (DTPS) interconnects 150, and may be coupled to the dies 114-3, 114-5, 114-6 in the second layer 104-2 by die-to-die (DTD) interconnects 130. The die 114-3 in the second layer 104-2 may be coupled to the package substrate by multi-level (ML) interconnects 152. The ML interconnects 152 may be high speed signal interconnects. In particular, the top surface of the package substrate 102 may include a set of conductive contacts 146. The die 114-2 may include a set of conductive contacts 122 on the bottom surface of the die, and a set of conductive contacts 124 on the top surface of the die. The dies 114-3, 114-5, 114-6 may include a set of conductive contacts 122 on the bottom surface of the die. As shown for the die 114-2, the conductive contacts 122 on the bottom surface of the die 114-2 may be electrically and mechanically coupled to the conductive contacts 146 on the top surface of the package substrate 102 by DTPS interconnects 150, and the conductive contacts 124 on the top surface of the die 114-2 may be electrically and mechanically coupled to the conductive contacts 122 on the bottom surface of the dies 114-3, 114-5, and 114-6 by DTD interconnects 130. As shown for the die 114-3, the conductive contacts 122 on the bottom surface of the die 114-3 further may be electrically and mechanically coupled to the conductive contacts 146 on the top surface of the package substrate by ML interconnects 152.

The conductive pillars 192 may be formed of any appropriate conductive material, such as copper, silver, nickel, gold, aluminum, or other metals or alloys, for example. The conductive pillars 192 of the MCI 190 may be formed using any suitable process, including, for example, the process described with reference to FIG. 4. In some embodiments, the conductive pillars 192 disclosed herein may have a pitch between 50 microns and 500 microns. As used herein, pitch is measured center-to-center (e.g., from a center of a conductive pillar to a center of an adjacent conductive pillar). The MCI 190 may improve the performance of the microelectronic assembly by more efficiently delivering power to the one or more dies 114. The conductive pillars 192 of the MCI 190 may have any suitable size and shape. In some embodiments, the conductive pillars 192 may have a circular, rectangular, or other shaped cross-section.

The magnetic material 194 surrounding the conductive pillar 192 may be formed of any suitable magnetic material, such as a ferromagnetic material. In some embodiments, suitable magnetic materials may include iron, nickel, cobalt, or nickel-iron alloys (e.g., Mu metals and/or permalloys). In some embodiments, suitable magnetic materials may include lanthanide and/or actinide elements, cobalt-zirconium-tantalum (CZT) alloy, semiconducting or semi-metallic Heusler compounds, and non-conducting (ceramic) ferrites. In some embodiments, suitable ferrite materials may include any of nickel, manganese, zinc, and/or cobalt cations, in addition to iron. In some embodiments, ferrite materials may include barium and/or strontium cations. In some embodiments, suitable Heusler compounds may include any of manganese, iron, cobalt, molybdenum, nickel, copper, vanadium, indium, aluminum, gallium, silicon, germanium, tin, and/or antimony. In some embodiments, suitable magnetic materials may include Heusler alloy, Co, Fe, Ni, Gd, B, Ge, Ga, permalloy, or yttrium iron garnet (YIG), where the Heusler alloy is a material which includes one or more of: Cu, Mn, Al, In, Sn, Ni, Sb, Ga, Co, Fe, Si, Pd, Sb, V, Ru, Cu₂MnAl, Cu₂MnIn, Cu₂MnSn, Ni₂MnAl, Ni₂MnIn, Ni₂MnSn, Ni₂MnSb, Ni₂MnGa Co₂MnAl, Co₂MnSi, Co₂MnGa, Co₂MnGe, Pd₂MnAl, Pd₂MnIn, Pd₂MnSn, Pd₂MnSb, Co₂FeSi, Co₂FeAl, Fe₂VAl, Mn₂VGa, Co₂FeGe, MnGa, MnGaRu, or Mn₃X, where ‘X’ is one of Ga or Ge. In some embodiments, suitable magnetic materials may include Pt, Pd, W, Ce, Al, Li, Mg, Na, Cr₂O₃, CoO, Dy, Dy₂O, Er, Er₂O₃, Eu, Eu₂O₃, Gd, Gd₂O₃, FeO, Fe₂O₃, Nd, Nd₂O₃, KO2, Pr, Sm, Sm₂O₃, Tb, Tb₂O₃, Tm, Tm₂O₃, V, V₂O₃ or epoxy material with particles of a magnetic alloy. In some embodiments, a magnetic alloy can be an alloy formed of one or more of: Pt, Pd, W, Ce, Al, Li, Mg, Na, Cr, Co, Dy, Er, Eu, Gd, Fe, Nd, K, Pr, Sm, Tb, Tm, or V. In some embodiments, a magnetic material may be formed of a dielectric with magnetic particles or flakes. For example, a non-conductive organic or inorganic material may have magnetic particles or flakes, such as iron, nickel, cobalt, and their alloys, where the magnetic particles have a diameter between 5 nanometers and 500 nanometers, and are distributed throughout the dielectric material. In some embodiments, the magnetic material used may depend on the desired characteristics for a particular MCI. For example, in some embodiments, a highly permeable magnetic material that may saturate under relatively light loads may be used to create MCIs for IVRs that supply light loads at high efficiency. In some embodiments, a magnetic material having lower permeability with a high saturation point may be used to create MCIs for IVRs that supply heavier loads.

The magnetic material 194 may be formed using any suitable process, including, for example, the process described with reference to FIG. 4. A magnetic material 194 may be formed to at least partially surround a conductive pillar 192. In some embodiments, the magnetic material 194 may be formed to completely surround a conductive pillar 192, such that the magnetic material 194 forms a sleeve around the conductive pillar 192. As used herein, “surrounded by a magnetic material” may refer to partly surrounded as well as wholly surrounded. For example, in some embodiments, surrounded by a magnetic material may refer to a conductive pillar wholly surrounded by a magnetic material around a diameter and partly surround by a magnetic material along a height (e.g., z-height or thickness). In some embodiments, surrounded by a magnetic material may refer to a conductive pillar wholly surrounded by a magnetic material along a height and partly surrounded by a magnetic material around a diameter (e.g., as shown below in FIG. 2C). In some embodiments, surrounded by a magnetic material may refer to a conductive pillar partly surrounded by a magnetic material along a height and partly surrounded by a magnetic material around a diameter. In some embodiments, surrounded by a magnetic material may refer to a conductive pillar wholly surrounded by a magnetic material along a height and wholly surrounded by a magnetic material around a diameter. In some embodiments, surrounded by a magnetic material may refer to a conductive pillar embedded in a magnetic material. In some embodiments, the package substrate 102 may be formed using a lithographically defined via packaging process. In some embodiments, the package substrate 102 may be manufactured using standard organic package manufacturing processes, and thus the package substrate 102 may take the form of an organic package. In some embodiments, the package substrate 102 may be a set of redistribution layers formed on a panel carrier by laminating or spinning on a dielectric material, and creating conductive vias and lines by laser drilling and plating. In some embodiments, the package substrate 102 may be formed on a removable carrier using any suitable technique, such as a redistribution layer technique. Any method known in the art for fabrication of the package substrate 102 may be used, and for the sake of brevity, such methods will not be discussed in further detail herein.

In some embodiments, the package substrate 102 may be a lower density medium and the die 114 (e.g., the die 114-2) may be a higher density medium or have an area with a higher density medium. As used herein, the term “lower density” and “higher density” are relative terms indicating that the conductive pathways (e.g., including conductive interconnects, conductive lines, and conductive vias) in a lower density medium are larger and/or have a greater pitch than the conductive pathways in a higher density medium. In some embodiments, a higher density medium may be manufactured using a modified semi-additive process or a semi-additive build-up process with advanced lithography (with small vertical interconnect features formed by advanced laser or lithography processes), while a lower density medium may be a printed circuit board (PCB) manufactured using a standard PCB process (e.g., a standard subtractive process using etch chemistry to remove areas of unwanted copper, and with coarse vertical interconnect features formed by a standard laser process). In other embodiments, the higher density medium may be manufactured using semiconductor fabrication process, such as a single damascene process or a dual damascene process.

In some embodiments, as shown on the die 114-2, the DTPS interconnects 150 may have a different pitch on the same die. In another example, the die 114-2 on the top surface may have DTD interconnects 130 that may have a different pitch on the same surface. A die 114 that has interconnects 130 of different pitches at a same surface may be referred to as a mixed-pitch die 114. In some embodiments, the DTD interconnects may have a pitch between 5 microns and 200 microns (e.g., between 5 microns and 100 microns). In some embodiments, the DTPS interconnects may have a pitch between 50 microns and 800 microns (e.g., between 100 microns and 500 microns).

Although FIG. 1A shows the die 114-2 as double-sided dies and the dies 114-3, 114-5, and 114-6 as single-sided dies, the dies 114 may be a single-sided or a double-sided die and may be a single-pitch die or a mixed-pitch die. In some embodiments, additional components may be disposed on the top surface of the dies 114-3, 114-5, and/or 114-6. Additional passive components, such as surface-mount resistors, capacitors, and/or inductors, may be disposed on the top surface or the bottom surface of the package substrate 102, or embedded in the package substrate 102. In this context, a double-sided die refers to a die that has connections on both surfaces. In some embodiments, a double-sided die may include through silicon vias (TSVs) to form connections on both surfaces. The active surface of a double-sided die, which is the surface containing one or more active devices and a majority of interconnects, may face either direction depending on the design and electrical requirements.

Placing dies in separate layers such that the dies at least partially overlap may reduce routing congestion and may improve utilization of the dies by enabling a die in a non-adjacent layer to be connected to a package substrate by any of the ML interconnects disclosed herein. In some embodiments, a first die may be connected to a second die in a non-adjacent layer by any of the ML interconnects disclosed herein. The dies 114 may be singled-sided dies or double-sided dies and may be a single-pitch die or a mixed-pitch die.

Although FIG. 1A shows the dies 114 in a particular arrangement, the dies 114 may be in any suitable arrangement. For example, a die 114-3 may extend over a die 114-2 by an overlap distance 191, and a die 114-5 may extend over a die 114-2 by an overlap distance 193. The overlap distances 191, 193 may be any suitable distance. In some embodiments, the overlap distance 191, 193 may be between 0.5 millimeters and 50 millimeters (e.g., between 0.75 millimeters and 20 millimeters, or approximately 10 millimeters). In some embodiments, the overlap distance 191, 193 may be between 0.25 millimeters and 25 millimeters. In some embodiments, the overlap distance 191, 193 may be between 0.25 millimeters and 5 millimeters.

In the embodiment of FIG. 1, the die 114-2 may provide high density interconnect routing in a localized area of the microelectronic assembly 100. In some embodiments, the presence of the die 114-2 may support direct chip attach of fine-pitch semiconductor dies (e.g., the die 114-6) that cannot be attached entirely directly to the package substrate 102. In particular, as discussed above, the die 114-2 may support trace widths and spacings that are not achievable in the package substrate 102. The proliferation of wearable and mobile electronics, as well as Internet of Things (IoT) applications, are driving reductions in the size of electronic systems, but limitations of the PCB manufacturing process and the mechanical consequences of thermal expansion during use have meant that chips having fine interconnect pitch cannot be directly mounted to a PCB. Various embodiments of the microelectronic assemblies 100 disclosed herein may be capable of supporting chips with high density interconnects and chips with low-density interconnects without sacrificing performance or manufacturability.

The microelectronic assembly 100 of FIG. 1A may also include a circuit board (not shown). The package substrate 102 may be coupled to the circuit board by second-level interconnects at the bottom surface of the package substrate 102. The second-level interconnects may be any suitable second-level interconnects, including solder balls for a ball grid array arrangement, pins in a pin grid array arrangement or lands in a land grid array arrangement. The circuit board may be a motherboard, for example, and may have other components attached to it. The circuit board may include conductive pathways and other conductive contacts for routing power, ground, and signals through the circuit board, as known in the art. In some embodiments, the second-level interconnects may not couple the package substrate 102 to a circuit board, but may instead couple the package substrate 102 to another IC package, an interposer, or any other suitable component. In some embodiments, the multi-layer die subassembly may not be coupled to a package substrate 102, but may instead be coupled to a circuit board, such as a PCB.

The microelectronic assembly 100 of FIG. 1A may also include an underfill material 127. In some embodiments, the underfill material 127 may extend between one or more of the dies and the integrated MCIs 190. In some embodiments, the underfill material 127 may extend between one or more of the dies 114 and the package substrate 102 around the associated DTPS interconnects 150. In some embodiments, the underfill material 127 may extend between different ones of the dies 114 around the associated DTD interconnects 130. The underfill material 127 may be an insulating material, such as an appropriate epoxy material. In some embodiments, the underfill material 127 may include a capillary underfill, non-conductive film (NCF), or molded underfill. In some embodiments, the underfill material 127 may include an epoxy flux that assists with soldering the die 114-2 to the package substrate 102 when forming the DTPS interconnects 150, and then polymerizes and encapsulates the DTPS interconnects 150. The underfill material 127 may be selected to have a coefficient of thermal expansion (CTE) that may mitigate or minimize the stress between the dies 114 and the package substrate 102 arising from uneven thermal expansion in the microelectronic assembly 100. In some embodiments, the CTE of the underfill material 127 may have a value that is intermediate to the CTE of the package substrate 102 (e.g., the CTE of the dielectric material of the package substrate 102) and a CTE of the dies 114.

The DTPS interconnects 150 disclosed herein may take any suitable form. In some embodiments, a set of DTPS interconnects 150 may include solder (e.g., solder bumps or balls that are subject to a thermal reflow to form the DTPS interconnects 150). In some embodiments, a set of DTPS interconnects 150 may include an anisotropic conductive material, such as an anisotropic conductive film or an anisotropic conductive paste. An anisotropic conductive material may include conductive materials dispersed in a non-conductive material.

The DTD interconnects 130 disclosed herein may take any suitable form. The DTD interconnects 130 may have a finer pitch than the DTPS interconnects 150 in a microelectronic assembly. In some embodiments, the dies 114 on either side of a set of DTD interconnects 130 may be unpackaged dies, and/or the DTD interconnects 130 may include small conductive bumps (e.g., copper bumps) attached to the conductive contacts 124 by solder. The DTD interconnects 130 may have too fine a pitch to couple to the package substrate 102 directly (e.g., to fine to serve as DTPS interconnects 150). In some embodiments, a set of DTD interconnects 130 may include solder. In some embodiments, a set of DTD interconnects 130 may include an anisotropic conductive material, such as any of the materials discussed above. In some embodiments, the DTD interconnects 130 may be used as data transfer lanes, while the DTPS interconnects 150 may be used for power and ground lines, among others. In some embodiments, some or all of the DTD interconnects 130 in a microelectronic assembly 100 may be metal-to-metal interconnects (e.g., copper-to-copper interconnects, or plated interconnects). In such embodiments, the conductive contacts 122, 124 on either side of the DTD interconnect 130 may be bonded together (e.g., under elevated pressure and/or temperature) without the use of intervening solder or an anisotropic conductive material. Any of the conductive contacts disclosed herein (e.g., the conductive contacts 122, 124, and/or 146) may include bond pads, solder bumps, conductive posts, or any other suitable conductive contact, for example. In some embodiments, some or all of the DTD interconnects 130 in a microelectronic assembly 100 may be solder interconnects that include a solder with a higher melting point than a solder included in some or all of the DTPS interconnects 150. For example, when the DTD interconnects 130 in a microelectronic assembly 100 are formed before the DTPS interconnects 150 are formed (e.g., as discussed below with reference to FIG. 4), solder-based DTD interconnects 130 may use a higher-temperature solder (e.g., with a melting point above 200 degrees Celsius), while the DTPS interconnects 150 may use a lower-temperature solder (e.g., with a melting point below 200 degrees Celsius). In some embodiments, a higher-temperature solder may include tin; tin and gold; or tin, silver, and copper (e.g., 96.5% tin, 3% silver, and 0.5% copper). In some embodiments, a lower-temperature solder may include tin and bismuth (e.g., eutectic tin bismuth) or tin, silver, and bismuth. In some embodiments, a lower-temperature solder may include indium, indium and tin, or gallium.

In the microelectronic assemblies 100 disclosed herein, some or all of the DTPS interconnects 150 may have a larger pitch than some or all of the DTD interconnects 130. DTD interconnects 130 may have a smaller pitch than DTPS interconnects 150 due to the greater similarity of materials in the different dies 114 on either side of a set of DTD interconnects 130 than between the die 114 and the package substrate 102 on either side of a set of DTPS interconnects 150. In particular, the differences in the material composition of a die 114 and a package substrate 102 may result in differential expansion and contraction of the die 114 and the package substrate 102 due to heat generated during operation (as well as the heat applied during various manufacturing operations). To mitigate damage caused by this differential expansion and contraction (e.g., cracking, solder bridging, etc.), the DTPS interconnects 150 may be formed larger and farther apart than DTD interconnects 130, which may experience less thermal stress due to the greater material similarity of the pair of dies 114 on either side of the DTD interconnects. In some embodiments, the DTPS interconnects 150 disclosed herein may have a pitch between 80 microns and 300 microns, while the DTD interconnects 130 disclosed herein may have a pitch between 7 microns and 100 microns.

The multi-layer die subassembly 104 may include an insulating material (e.g., a dielectric material formed in multiple layers, as known in the art) to form the multiple layers and to embed one or more dies in a layer. In some embodiments, the insulating material of the multi-layer die subassembly may be a dielectric material, such as an organic dielectric material, a fire retardant grade 4 material (FR-4), bismaleimide triazine (BT) resin, polyimide materials, glass reinforced epoxy matrix materials, or low-k and ultra low-k dielectric (e.g., carbon-doped dielectrics, fluorine-doped dielectrics, porous dielectrics, and organic polymeric dielectrics). The multi-layer die subassembly 104 may include one or more ML interconnects through the dielectric material (e.g., including conductive vias and/or conductive pillars, as shown). The multi-layer die subassembly 104 may have any suitable dimensions. For example, in some embodiments, a thickness of the multi-layer die subassembly 104 may be between 100 um and 2000 um. In some embodiments, the multi-layer die subassembly 104 may be a composite die, such as stacked dies. The multi-layer die subassembly 104 may have any suitable number of layers, any suitable number of dies, and any suitable die arrangement. For example, in some embodiments, the multi-layer die subassembly 104 may have between 3 and 20 layers of dies. In some embodiments, the multi-layer die subassembly 104 may include a layer having between 2 and 10 dies.

The package substrate 102 may include an insulating material (e.g., a dielectric material formed in multiple layers, as known in the art) and one or more conductive pathways to route power, ground, and signals through the dielectric material (e.g., including conductive traces and/or conductive vias, as shown). In some embodiments, the insulating material of the package substrate 102 may be a dielectric material, such as an organic dielectric material, a fire retardant grade 4 material (FR-4), BT resin, polyimide materials, glass reinforced epoxy matrix materials, organic dielectrics with inorganic fillers or low-k and ultra low-k dielectric (e.g., carbon-doped dielectrics, fluorine-doped dielectrics, porous dielectrics, and organic polymeric dielectrics). In particular, when the package substrate 102 is formed using standard PCB processes, the package substrate 102 may include FR-4, and the conductive pathways in the package substrate 102 may be formed by patterned sheets of copper separated by build-up layers of the FR-4. The conductive pathways in the package substrate 102 may be bordered by liner materials, such as adhesion liners and/or barrier liners, as suitable.

The dies 114 disclosed herein may include an insulating material (e.g., a dielectric material formed in multiple layers, as known in the art) and multiple conductive pathways formed through the insulating material. In some embodiments, the insulating material of a die 114 may include a dielectric material, such as silicon dioxide, silicon nitride, oxynitride, polyimide materials, glass reinforced epoxy matrix materials, or a low-k or ultra low-k dielectric (e.g., carbon-doped dielectrics, fluorine-doped dielectrics, porous dielectrics, organic polymeric dielectrics, photo-imagable dielectrics, and/or benzocyclobutene-based polymers). In some embodiments, the insulating material of a die 114 may include a semiconductor material, such as silicon, germanium, or a III-V material (e.g., gallium nitride), and one or more additional materials. For example, an insulating material may include silicon oxide or silicon nitride. The conductive pathways in a die 114 may include conductive traces and/or conductive vias, and may connect any of the conductive contacts in the die 114 in any suitable manner (e.g., connecting multiple conductive contacts on a same surface or on different surfaces of the die 114). Example structures that may be included in the dies 114 disclosed herein are discussed below with reference to FIG. 9. The conductive pathways in the dies 114 may be bordered by liner materials, such as adhesion liners and/or barrier liners, as suitable.

In some embodiments, the die 114 may include conductive pathways to route power, ground, and/or signals to/from other dies 114 included in the microelectronic assembly 100. For example, the die 114-2 may include TSVs, including a conductive material via, such as a metal via, isolated from the surrounding silicon or other semiconductor material by a barrier oxide), or other conductive pathways through which power, ground, and/or signals may be transmitted between the package substrate 102 and one or more dies 114 “on top” of the die 114-2 (e.g., in the embodiment of FIG. 1A, the dies 114-3, 114-5, and/or 114-6). In some embodiments, the die 114-2 may not route power and/or ground to the dies 114-3 and 114-5; instead, the die 114-2 may couple directly to power and/or ground lines in the package substrate 102 by ML interconnects 152 By allowing the dies 114-3 and 114-5 to couple directly to power and/or ground lines in the package substrate 102 via ML interconnects 152, such power and/or ground lines need not be routed through the die 114-2, allowing the die 114-2 to be made smaller or to include more active circuitry or signal pathways. In some embodiments, the die 114-2 may only include conductive pathways, and may not contain active or passive circuitry. In other embodiments, the die 114-2 may include active or passive circuitry (e.g., transistors, diodes, resistors, inductors, and capacitors, among others). In some embodiments, the die 114-2 may include one or more device layers including transistors (e.g., as discussed below with reference to FIG. 9). When the die 114-2 includes active circuitry, power and/or ground signals may be routed through the package substrate 102 and to the die 114-2 through the conductive contacts 122 on the bottom surface of the die 114-2. In some embodiments, the die 114-2 in the first layer 104-1, also referred to herein as the “base die,” may be thicker than the dies 114-3, 114-5, 114-6 in the second layer 104-2. The die 114-2 of the microelectronic assembly 100 may be a single-sided die (in the sense that the die 114-2 only has conductive contacts on a single surface), or, as shown, may be a double-sided die (in the sense that the die 114-2 has conductive contacts 122, 124 on two surfaces (e.g., a top surface and a bottom surface)), and may be a mixed-pitch die (in the sense that the die 114-2 has sets of conductive contacts 122, 124 with different pitches).

The elements of the microelectronic assembly 100 may have any suitable dimensions. Only a subset of the accompanying figures are labeled with reference numerals representing dimensions, but this is simply for clarity of illustration, and any of the microelectronic assemblies 100 disclosed herein may have components having the dimensions discussed herein. In some embodiments, the thickness 164 of the package substrate 102 may be between 0.1 millimeters and 3 millimeters (e.g., between 0.3 millimeters and 2 millimeters, between 0.25 millimeters and 0.8 millimeters, or approximately 1 millimeter).

Many of the elements of the microelectronic assembly 100 of FIG. 1A are included in other ones of the accompanying figures; the discussion of these elements is not repeated when discussing these figures, and any of these elements may take any of the forms disclosed herein. In some embodiments, individual ones of the microelectronic assemblies 100 disclosed herein may serve as a system-in-package (SiP) in which multiple dies 114 having different functionality are included. In such embodiments, the microelectronic assembly 100 may be referred to as an SiP.

FIG. 2A is a side, cross-sectional view of another example microelectronic assembly, in accordance with various embodiments. In the microelectronic assemblies 100 disclosed herein, the multi-layer die subassembly 104 may include a redistribution layer (RDL) 148, also referred to herein as a package substrate portion. For example, FIG. 2A illustrates an embodiment of a microelectronic assembly 100 in which a multi-layer die subassembly 104 has an RDL 148 below the first layer 104-1. The microelectronic assembly 100 may include MCI 190. The MCI 190 may include two terminals (e.g., a first conductive pillar 192-1 and a second conductive pillar 192-2) where both the first and second conductive pillars are surrounded by the magnetic material 194, as described above with reference to FIG. 1. The first and second conductive pillars 192 of the MCI 190 may be electrically coupled via a conductive pathway 196 in the RDL 148.

Although FIG. 2A shows a particular arrangement of a microelectronic assembly 100 including a single MCI 190 and three dies 114, a microelectronic assembly 100 may include any number and arrangement of MCIs 190, and any number and arrangement of dies 114. For example, a microelectronic assembly 100 may include two or more MCIs. In some embodiments, a microelectronic assembly 100 may include thirty or more MCIs. In some embodiments, a microelectronic assembly may include one hundred or more MCIs. As shown in FIG. 1A, the MCI 190 is a two-terminal MCI, which includes a first conductive pillar and a second conductive pillar surrounded by magnetic material and coupled via a conductive pathway. In some embodiments, two or more two-terminal MCIs may be electrically coupled by conductive pathways, as described above with reference to FIG. 1. In some embodiments, two or more two-terminal MCIs may be magnetically coupled and may function as a transformer having at least four terminals. A transformer may include three or more terminals coupled via alternating top and bottom conductive pathways, as described below with reference to FIG. 7. For example, a first two-terminal MCI and a second two-terminal MCI may be positioned in close proximity, such that the magnetic fields of the first MCI and the second MCI are coupled (e.g., in the same direction or positive coupling) and/or anti-coupled (e.g., in opposite directions or negative coupling). As used herein, the two MCIs are positioned in close proximity when a distance between the second conductive pillar of the first MCI and the first conductive pillar of the second MCI is between 50 microns and 2000 microns (e.g., the greatest distance is no more than four times the largest pitch between conductive pillars, where the largest pitch is 500 microns).

FIG. 2B is a top view schematic of the integrated MCI in the microelectronic assembly of FIG. 2A, in accordance with various embodiments. FIG. 2B is a top view schematic of MCI 190 showing the first and second conductive pillars 192 surrounded by the magnetic material 194 and electrically coupled by a conductive pathway 196 in the RDL 148 at the bottom surface of the conductive pillars (e.g., at a first surface 170-1), which is depicted by the dotted lines.

FIG. 2C is a top view schematic of the integrated MCI in the microelectronic assembly of FIG. 2A, in accordance with various embodiments. FIG. 2C is a top view schematic of MCI 190 showing the first and second conductive pillars 192 partially surrounded by the magnetic material 194 along a diameter (e.g., cross-section) of the conductive pillars 192.

FIG. 3A is a side, cross-sectional view of another example microelectronic assembly, in accordance with various embodiments. In the microelectronic assemblies 100 disclosed herein, the multi-layer die subassembly 104 may include more than one RDL 148. For example, FIG. 3A illustrates an embodiment of a microelectronic assembly 100 in which a multi-layer die subassembly 104 has two RDLs 148, a first RDL 148-1 below the first layer 104-1 and a second RDL 148-2 between the first layer 104-1 and the second layer 104-2. The microelectronic assembly 100 may include MCI 190. The MCI 190 may include four conductive pillars 192-1-192-4, where the first conductive pillar 192-1 and the fourth conductive pillar 192-4 are surrounded by the magnetic material 194, as described above with reference to FIG. 1. The first conductive pillar 192-1 may be electrically coupled to the second conductive pillar 192-2, and the third conductive pillar 192-3 may be electrically coupled the fourth conductive pillar 192-4 via conductive pathways 196A, 196B, respectively, in the first RDL 148-1. The second conductive pillar 192-2 may be electrically coupled to the third conductive pillar 192-3 via a conductive pathway in the second RDL 148-2. As shown in FIG. 3A, the MCI 190 may be described herein as two, two-terminal MCIs coupled is series.

FIG. 3B is a top view schematic of the integrated MCI in the microelectronic assembly of FIG. 3A, in accordance with various embodiments. FIG. 3B is a top view schematic of MCI 190 showing the first and fourth conductive pillars surrounded by the magnetic material 194, where the first conductive pillar is electrically coupled to the second conductive pillar and the third conductive pillar is electrically coupled to the fourth conductive pillar via conductive pathways 196A in the first RDL 148-1 at the bottom surface of the conductive pillars (e.g., at the first surface 170-1), which is depicted by the dotted lines, and the second conductive pillar is electrically coupled to the third conductive pillar via a conductive pathway 196B in the second RDL 148-2 at the top surface of the conductive pillars (e.g., at the second surface 170-2). In some embodiments, the second conductive pillar may be electrically coupled the third conductive pillar 192-3 via a conductive pathway in the multi-layer die subassembly 104 at the top surface of the conductive pillars (e.g., at a second surface 170-2).

FIGS. 4A-4B are side, cross-sectional views of example microelectronic assemblies, in accordance with various embodiments. FIG. 4A illustrates an embodiment of a microelectronic assembly 100 that may include a first MCI 190A and a second MCI 190B. The microelectronic assembly 100 may include a multi-layer die subassembly 104 having three-layers 104-1-104-3 and may further include an RDL 148 between the first layer 104-1 and the second layer 104-2. The first MCI 190A may include first and second conductive pillars 192 that extend through multiple layers of the multi-layer die subassembly 104. For example, as shown in FIG. 4A, the first and second conductive pillars 192 may extend through the first layer 104-1, the RDL 148, and the second layer 104-2. As shown in FIG. 4A, both the first and second conductive pillars 192 of the MCI 190A are surrounded by the magnetic material 194, however, this is simply exemplary and only a single conductive pillar may be surrounded by the magnetic material. The first and second conductive pillars 192 of the first MCI 190A may be electrically coupled via a conductive pathway 196A in the package substrate 102. In some embodiments, the first and second conductive pillars 192 of the first MCI 190A may be electrically coupled via a conductive pathway in the multi-layer die subassembly 104 (not shown). The second MCI 190B may include a first conductive pillar and a second conductive pillar 192 in an upper layer (e.g., the second layer 104-2) of the multi-layer die subassembly 104. The first and second conductive pillars 192 of the second MCI 190B may be electrically coupled via a conductive pathway in the RDL 148. In some embodiments, the second MCI 190B may include conductive pillars that extend through multiple layers of the multi-layer die subassembly 104. In some embodiments, the second MCI 190B may include a magnetic material 194 surrounding both first and second conductive pillars.

FIG. 4B illustrates an embodiment of a microelectronic assembly 100 that may include a prefabricated MCI subassembly 199 where an inductor may be embedded in a magnetic material and the MCI subassembly may be placed in a multi-layer die subassembly 104. The MCI subassembly 199 may include any suitable inductor, for example, a wire-bound inductor, a multi-layer ceramic inductor, and a thin-film inductor, and may be formed using any suitable technique as is known in the art. The prefabricated MCI subassembly 199 may be placed in a multi-layer die assembly as described below with reference to FIG. 5, in the same manner as a die 114 may be placed.

FIGS. 5A-5G are side, cross-sectional views of various stages in an example process for manufacturing the microelectronic assembly of FIG. 1, in accordance with various embodiments. Any suitable techniques may be used to manufacture the microelectronic assemblies disclosed herein. For example, FIGS. 5A-5G are side, cross-sectional views of various stages in an example process for manufacturing the microelectronic assembly 100 of FIG. 1, in accordance with various embodiments. Although the operations discussed below with reference to FIGS. 5A-5G (and others of the accompanying drawings representing manufacturing processes) are illustrated in a particular order, these operations may be performed in any suitable order. Additionally, although particular assemblies are illustrated in FIGS. 5A-5G (and others of the accompanying drawings representing manufacturing processes), the operations discussed below with reference to FIGS. 5A-5G may be used to form any suitable assemblies. In the embodiment of FIGS. 5A-5G, the MCI 190 may first be assembled into a composite die, and then the composite die may be coupled to the package substrate 102. This approach may allow for tighter tolerances, and may be particularly desirable for integrating a plurality of MCI 190, for relatively small dies 114, and for a composite die having three or more layers.

FIG. 5A illustrates an assembly 500A including a carrier 502 subsequent to forming conductive pillars 534 on the top surface of the carrier 502. The carrier 502 may include any suitable material for providing mechanical stability during manufacturing operations. The conductive pillars 534 may be disposed to form one or more de-population regions 555 in which no conductive pillars are present. The conductive pillars 534 may take the form of any of the embodiments disclosed herein, and may be formed using any suitable technique, for example, a lithographic process or an additive process, such as cold spray or 3-dimensional printing. For example, the conductive pillars 534 may be formed by depositing, exposing, and developing a photoresist layer on the top surface of the carrier 502. The photoresist layer may be patterned to form cavities in the shape of the conductive pillars. Conductive material, such as copper, may be deposited in the openings in the patterned photoresist layer to form the conductive pillars 534. The conductive material may be depositing using any suitable process, such as electroplating, sputtering, or electroless plating. The photoresist may be removed to expose the conductive pillars 534. In another example, a photo-imagable dielectric may be used to form the conductive pillars 534. In some embodiments, a seed layer (not shown) may be formed on the top surface of the carrier 502 prior to depositing the photoresist material and the conductive material. The seed layer may be any suitable conductive material, including copper. The seed layer may be removed, after removing the photoresist layer, using any suitable process, including chemical etching, among others. In some embodiments, the seed layer may be omitted.

The conductive pillars may have any suitable dimensions and may span one or more layers. For example, in some embodiments, an individual conductive pillar may have an aspect ratio (height:diameter) between 1:1 and 4:1 (e.g., between 1:1 and 3:1). In some embodiments, an individual conductive pillar may have a diameter (e.g., cross-section) between 10 microns and 1000 microns. For example, an individual conductive pillar may have a diameter between 50 microns and 400 microns. In some embodiments, an individual conductive pillar may have a height (e.g., z-height or thickness) between 50 and 500 microns. The conductive pillars may have any suitable cross-sectional shape, for example, square, triangular, and oval, among others.

FIG. 5B illustrates an assembly 500B subsequent to placing the die 114-2 in the de-population region 555 of the assembly 500A (FIG. 5A) and providing a photo-imagable dielectric (PID) 530 around the die 114 and the conductive pillars 534. The PID 530 may be deposited using any suitable technique, for example, by lamination. In some embodiments, a non-photo-definable material may be used in place of the PID, such as a dielectric mask, and removed, for example, using reactive ion etching (RIE). The die 114 may be placed on the carrier 502 using any suitable technique, such as die attach film (DAF). The die 114 may include a non-electrical material layer (not shown) or a carrier (not shown) on top of the die 114 that provides improved mechanical stability. The non-electrical material layer, which is an inactive portion of the die 114, may include silicon, ceramic, or quartz, among other materials. The non-electrical material layer may be attached to the die 114 using any suitable technique, including, for example, a release layer. The release layer (also referred to herein as a debonding layer) may include a temporary adhesive, or other material that releases when exposed to heat or light, for example. The non-electrical material layer may be removed using any suitable technique, including, for example, grinding, etching, such as RIE or chemical etching, or, if the debonding layer includes a photo-reactive or thermally-reactive material, applying light or heat. The carrier may include any suitable material to provide mechanical stability. The carrier may be attached to the die 114 using any suitable technique, including, for example, a removable adhesive. MCI subassemblies, such as the MCI subassemblies of FIGS. 4B, 6A and 6B may be placed on the carrier, or placed in upper layers as described below with reference to FIG. 5F, using a same or similar technique to placing a die 114, such using as pick and place tooling.

FIG. 5C illustrates an assembly 500C subsequent to the PID 530 being exposed and developed to selectively reveal the conductive pillars 534 to be surrounded by the magnetic material. The PID 530 forms openings 531 around the selected conductive pillars for providing magnetic material.

FIG. 5D illustrates an assembly 500D subsequent to providing a magnetic material 594 in the openings 531 formed in the PID 530. The magnetic material 594 may be deposited using any suitable technique, such as stencil printing, stenciless printing, electroplating, or sputtering. In some embodiments, the magnetic material is cured subsequent to deposition. The technique used to deposit the magnetic material may depend on the type of magnetic material used. In some embodiments, the same magnetic material may be used to surround or coat the conductive pillars. In some embodiments, a different magnetic material may be used to surround or coat the conductive pillars, and the magnetic material used may depend on the desired characteristics for a particular MCI. The magnetic material 594 may be any suitable magnetic material as described above with reference to FIG. 1.

FIG. 5E illustrates an assembly 500E subsequent to removing the PID 530, to providing an insulating material 533 around the die 114-2, and the conductive pillars 534, including the magnetic material, and to forming a conductive pathway 596 between two conductive pillars of the assembly 500D (FIG. 5D). In some embodiments, the insulating material 533 may be initially deposited on and over the tops of the die 114-2, and the conductive pillars 534, then, polished back to expose the conductive contacts 124 at the top surface of the die 114-2 and the top surfaces of the conductive pillars 534. In some embodiments, the insulating material 533 is a mold material, such as an organic polymer with inorganic silica particles. In some embodiments, the insulating material 533 is a dielectric material. In some embodiments, the dielectric material may include an organic dielectric material, a fire retardant grade 4 material (FR-4), BT resin, polyimide materials, glass reinforced epoxy matrix materials, or low-k and ultra low-k dielectric (e.g., carbon-doped dielectrics, fluorine-doped dielectrics, porous dielectrics, and organic polymeric dielectrics). The dielectric material may be formed using any suitable process, including lamination, or slit coating and curing. If the dielectric layer is formed to completely cover the conductive pillars 534 and the die 114-2, the dielectric layer may be removed to expose the conductive contacts 124 at the top surface of the die 114-2 and the top surfaces of the conductive pillars 534 using any suitable technique, including grinding, or etching, such as a wet etch, a dry etch (e.g., a plasma etch), a wet blast, or a laser ablation (e.g., using excimer laser). In some embodiments, the thickness of the insulating material 533 may be minimized to reduce the etching time required. The conductive pathway 596 may be formed using any suitable technique, including forming an RDL (not shown) on the top surface of the assembly 500E. The RDL may be manufactured using any suitable technique, such as a PCB technique or a redistribution layer technique.

FIG. 5F illustrates an assembly 500F subsequent to placing the dies 114-3, 114-5, 114-6, and providing an insulating material 533 around the dies. The dies 114-3, 114-5 may be coupled to the die 114-2 by DTD interconnects 130. The dies 114-3, 114-5 may be coupled to the conductive pillars of the MCI and die 114-3 may be coupled to the ML interconnects 152. Additional layers of the composite die may be built up by repeating the process as described with respect to FIGS. 5A-5E.

FIG. 5G illustrates an assembly 500G subsequent to removal of the carrier 502 and coupling to a package substrate 102. The conductive pillars of the MCI, as described above with reference to FIG. 1, may be coupled via conductive pathways in the package substrate. If multiple composite dies are manufactured together, the composite dies may be singulated after removal of the carrier 502. Further operations may be performed as suitable either before or after singulating (e.g., depositing a mold material, attaching a heat spreader, depositing a solder resist layer, attaching solder balls for coupling to a package substrate or to a circuit board, etc.). Although assembly 500G has conductive contacts 122 on the bottom surface of the die 114-2 and on the bottom surface of the conductive pillars of the MCI for electrically coupling to a package substrate or a circuit board, in some embodiments, the dies 114-3, 114-5, and/or 114-6 may include conductive contacts on a top surface and the MCI may be embedded within the composite die such that the assembly may be inverted or “flipped” and coupled to a package substrate or circuit board via interconnects on the top surface of the dies 114-3, 114-3, and/or 114-6.

FIG. 6A is a side, cross-sectional view of a microelectronic assembly 100, in accordance with various embodiments. The microelectronic assembly 100 may include a package substrate 102 coupled to a multi-layer die subassembly 104 having a prefabricated MCI subassembly, where the MCI subassembly is formed via an interposer (e.g., MCI interposer 197A). Any suitable technique may be used to form an MCI interposer 197A. For example, an MCI interposer 197A may be formed using a passive silicon die or organic package with TSVs, which are the conductive pillars of the MCI. The silicon may be drilled to form the TSVs, for example, by a laser or mechanical drill, and filled with magnetic material. The magnetic material after curing may be drilled to form a smaller diameter TSV and filled with conductive material, such as by copper plating. The TSVs may be coupled by conductive pathways formed on the top and/or bottom surface of the interposer. The MCI interposer 197A may be coupled to a die 114-3 via interconnects 130. The MCI interposer 197A may be coupled to a die 114-2 and/or composite die using any suitable technique, for example, any of the processes described above with reference to FIG. 5, among others. The MCI interposer 197A may include four conductive pillars having conductive pathways in the interposer at a bottom surface coupling the first and second conductive pillars and the third and fourth conductive pillars, and a conductive pathway in the interposer at a top surface coupling the second and third conductive pillars.

FIG. 6B is a side, cross-sectional view of a microelectronic assembly 100, in accordance with various embodiments. The microelectronic assembly 100 may include a package substrate 102 coupled to a multi-layer die subassembly 104 having a prefabricated MCI subassembly, where the MCI subassembly is formed via an interposer (e.g., MCI interposer 197B). Any suitable technique may be used to form an MCI interposer 197B, including techniques described above with reference to FIG. 6A. The MCI interposer 197B may include interconnects 150 on a bottom surface for coupling to a package substrate, such that the first and second conductive pillars and the third and fourth conductive pillars are coupled via conductive pathways in the package substrate 102. The MCI interposer 197B may include four conductive pillars having conductive pathways in the package substrate coupling the first and second conductive pillars and the third and fourth conductive pillars, and a conductive pathway in the interposer at a top surface coupling the second and third conductive pillars.

FIG. 7A is a top view schematic of an example transformer, in accordance with various embodiments. A transformer 700 may be prefabricated subassembly, for example, manufactured via an interposer as described above with reference to FIG. 6, and may be included in any of the microelectronic assemblies 100 disclosed herein as described above with reference to FIG. 6. As shown in FIG. 7A, an example transformer 700 may include two solenoids interwound together. The transformer 700 may include six conductive pillars 792-1-792-6 and two conductive contacts 730-1, 730-2 electrically coupled via conductive pathways 796-1-796-6 in a cross-woven pattern. Although FIG. 7A depicts all conductive pillars 792-1-792-6 embedded in magnetic material 794, any number of the conductive pillars 792 may be embedded in a magnetic material 794. In some embodiments, only one of the conductive pillars is embedded in a magnetic material. In some embodiments, two or more of the conductive pillars are embedded in a magnetic material.

FIG. 7B are side, cross-sectional schematics of the example transformer of FIG. 7A, in accordance with various embodiments. As shown in FIGS. 7A and 7B, the first conductive pillar 792-1 may be coupled to the third conductive pillar 792-3 via conductive pathway 796-1 along a bottom surface of the conductive pillars, as depicted by the dotted line, the third conductive pillar 792-3 may be coupled to the fourth conductive pillar 792-4 via conductive pathway 796-2 at the top surface of the conductive pillars, as depicted by the solid line, and the fourth conductive pillar 792-4 may be coupled to the sixth conductive pillar 792-6 via conductive pathway 796-3, at the bottom surface of the conductive pillars. The first conductive contact 730-1 may be coupled to the second conductive pillar 792-2 via conductive pathway 796-4 at the top surface of the conductive pillar, the second conductive pillar 792-2 may be coupled to the fifth conductive pillar 792-5 via conductive pathway 796-5 at the bottom surface of the conductive pillar, and the fifth conductive pillar 792-5 may be coupled to the second conductive contact 730-2 via conductive pathway 796-6 at the top surface of the conductive pillar. As shown in FIG. 7A, the individual conductive pathways crossover to form the transformer and the conductive pillars 792-1-792-6 are embedded in a magnetic material 794.

Although the microelectronic assemblies 100 disclosed herein show a particular number and arrangement of MCIs, dies, and interconnects, any number and arrangement of MCIs, dies, and interconnects may be used, and may further include one or more RDLs and package substrate portions. Further, although the microelectronic assemblies 100 disclosed herein show a particular arrangement of MCIs, an MCI may have any number and arrangement of coupled conductive pillars as well as any number and arrangement of coupled conductive pillars surrounded in magnetic material.

The microelectronic assemblies 100 disclosed herein may be used for any suitable application. For example, in some embodiments, a microelectronic assembly 100 may be used to provide an ultra-high density and high bandwidth interconnect for field programmable gate array (FPGA) transceivers and III-V amplifiers. More generally, the microelectronic assemblies 100 disclosed herein may allow “blocks” of different kinds of functional circuits to be distributed into different ones of the dies 114, instead of having all of the circuits included in a single large die, per some conventional approaches. In some such conventional approaches, a single large die would include all of these different circuits to achieve high bandwidth, low loss communication between the circuits, and some or all of these circuits may be selectively disabled to adjust the capabilities of the large die. However, because the ML interconnects 152, and/or the DTD interconnects 130 of the microelectronic assemblies 100 may allow high bandwidth, low loss communication between different ones of the dies 114 and different ones of the dies 114 and the package substrate 102, different circuits may be distributed into different dies 114, reducing the total cost of manufacture, improving yield, and increasing design flexibility by allowing different dies 114 (e.g., dies 114 formed using different fabrication technologies) to be readily swapped to achieve different functionality.

In another example, a die 114-2 that includes active circuitry in a microelectronic assembly 100 may be used to provide an “active” bridge between other dies 114 (e.g., between the dies 114-1 and 114-3, or between the dies 114-1 and 114-6, in various embodiments). In another example, the die 114-1 in a microelectronic assembly 100 may be a processing device (e.g., a central processing unit, a graphics processing unit, a FPGA, a modem, an applications processor, etc.), and the die 114-2 may include high bandwidth memory, transceiver circuitry, and/or input/output circuitry (e.g., Double Data Rate transfer circuitry, Peripheral Component Interconnect Express circuitry, etc.). In some embodiments, the die 114-1 may include a set of conductive contacts 124 to interface with a high bandwidth memory die 114-2, a different set of conductive contacts 124 to interface with an input/output circuitry die 114-2, etc. The particular high bandwidth memory die 114-2, input/output circuitry die 114-2, etc. may be selected for the application at hand.

In another example, the die 114-2 in a microelectronic assembly 100 may be a cache memory (e.g., a third level cache memory), and one or more dies 114-1, 114-3, and/or 114-6 may be processing devices (e.g., a central processing unit, a graphics processing unit, a FPGA, a modem, an applications processor, etc.) that share the cache memory of the die 114-2.

In another example, a die 114 may be a single silicon substrate or may be a composite die, such as a memory stack.

The microelectronic assemblies 100 disclosed herein may be included in any suitable electronic component. FIGS. 8-11 illustrate various examples of apparatuses that may include, or be included in, any of the microelectronic assemblies 100 disclosed herein.

FIG. 8 is a top view of a wafer 1500 and dies 1502 that may be included in any of the microelectronic assemblies 100 disclosed herein (e.g., as any suitable ones of the dies 114). The wafer 1500 may be composed of semiconductor material and may include one or more dies 1502 having IC structures formed on a surface of the wafer 1500. Each of the dies 1502 may be a repeating unit of a semiconductor product that includes any suitable IC. After the fabrication of the semiconductor product is complete, the wafer 1500 may undergo a singulation process in which the dies 1502 are separated from one another to provide discrete “chips” of the semiconductor product. The die 1502 may be any of the dies 114 disclosed herein. The die 1502 may include one or more transistors (e.g., some of the transistors 1640 of FIG. 9, discussed below), supporting circuitry to route electrical signals to the transistors, passive components (e.g., signal traces, resistors, capacitors, or inductors), and/or any other IC components. In some embodiments, the wafer 1500 or the die 1502 may include a memory device (e.g., a random access memory (RAM) device, such as a static RAM (SRAM) device, a magnetic RAM (MRAM) device, a resistive RAM (RRAM) device, a conductive-bridging RAM (CBRAM) device, etc.), a logic device (e.g., an AND, OR, NAND, or NOR gate), or any other suitable circuit element. Multiple ones of these devices may be combined on a single die 1502. For example, a memory array formed by multiple memory devices may be formed on a same die 1502 as a processing device (e.g., the processing device 1802 of FIG. 11) or other logic that is configured to store information in the memory devices or execute instructions stored in the memory array. In some embodiments, a die 1502 (e.g., a die 114) may be a central processing unit, a radio frequency chip, a power converter, or a network processor. Various ones of the microelectronic assemblies 100 disclosed herein may be manufactured using a die-to-wafer assembly technique in which some dies 114 are attached to a wafer 1500 that include others of the dies 114, and the wafer 1500 is subsequently singulated.

FIG. 9 is a cross-sectional side view of an IC device 1600 that may be included in any of the microelectronic assemblies 100 disclosed herein (e.g., in any of the dies 114). One or more of the IC devices 1600 may be included in one or more dies 1502 (FIG. 8). The IC device 1600 may be formed on a die substrate 1602 (e.g., the wafer 1500 of FIG. 8) and may be included in a die (e.g., the die 1502 of FIG. 8). The die substrate 1602 may be a semiconductor substrate composed of semiconductor material systems including, for example, n-type or p-type materials systems (or a combination of both). The die substrate 1602 may include, for example, a crystalline substrate formed using a bulk silicon or a silicon-on-insulator (SOI) substructure. In some embodiments, the die substrate 1602 may be formed using alternative materials, which may or may not be combined with silicon, that include, but are not limited to, germanium, indium antimonide, lead telluride, indium arsenide, indium phosphide, gallium arsenide, or gallium antimonide. Further materials classified as group II-VI, III-V, or IV may also be used to form the die substrate 1602. Although a few examples of materials from which the die substrate 1602 may be formed are described here, any material that may serve as a foundation for an IC device 1600 may be used. The die substrate 1602 may be part of a singulated die (e.g., the dies 1502 of FIG. 8) or a wafer (e.g., the wafer 1500 of FIG. 8).

The IC device 1600 may include one or more device layers 1604 disposed on the die substrate 1602. The device layer 1604 may include features of one or more transistors 1640 (e.g., metal oxide semiconductor field-effect transistors (MOSFETs)) formed on the die substrate 1602. The device layer 1604 may include, for example, one or more source and/or drain (S/D) regions 1620, a gate 1622 to control current flow in the transistors 1640 between the S/D regions 1620, and one or more S/D contacts 1624 to route electrical signals to/from the S/D regions 1620. The transistors 1640 may include additional features not depicted for the sake of clarity, such as device isolation regions, gate contacts, and the like. The transistors 1640 are not limited to the type and configuration depicted in FIG. 9 and may include a wide variety of other types and configurations such as, for example, planar transistors, non-planar transistors, or a combination of both. Non-planar transistors may include FinFET transistors, such as double-gate transistors or tri-gate transistors, and wrap-around or all-around gate transistors, such as nanoribbon and nanowire transistors.

Each transistor 1640 may include a gate 1622 formed of at least two layers, a gate dielectric and a gate electrode. The gate dielectric may include one layer or a stack of layers. The one or more layers may include silicon oxide, silicon dioxide, silicon carbide, and/or a high-k dielectric material. The high-k dielectric material may include elements such as hafnium, silicon, oxygen, titanium, tantalum, lanthanum, aluminum, zirconium, barium, strontium, yttrium, lead, scandium, niobium, and zinc. Examples of high-k materials that may be used in the gate dielectric include, but are not limited to, hafnium oxide, hafnium silicon oxide, lanthanum oxide, lanthanum aluminum oxide, zirconium oxide, zirconium silicon oxide, tantalum oxide, titanium oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, and lead zinc niobate. In some embodiments, an annealing process may be carried out on the gate dielectric to improve its quality when a high-k material is used.

The gate electrode may be formed on the gate dielectric and may include at least one p-type work function metal or n-type work function metal, depending on whether the transistor 1640 is to be a p-type metal oxide semiconductor (PMOS) or an n-type metal oxide semiconductor (NMOS) transistor. In some implementations, the gate electrode may consist of a stack of two or more metal layers, where one or more metal layers are work function metal layers and at least one metal layer is a fill metal layer. Further metal layers may be included for other purposes, such as a barrier layer. For a PMOS transistor, metals that may be used for the gate electrode include, but are not limited to, ruthenium, palladium, platinum, cobalt, nickel, conductive metal oxides (e.g., ruthenium oxide), and any of the metals discussed below with reference to an NMOS transistor (e.g., for work function tuning). For an NMOS transistor, metals that may be used for the gate electrode include, but are not limited to, hafnium, zirconium, titanium, tantalum, aluminum, alloys of these metals, carbides of these metals (e.g., hafnium carbide, zirconium carbide, titanium carbide, tantalum carbide, and aluminum carbide), and any of the metals discussed above with reference to a PMOS transistor (e.g., for work function tuning).

In some embodiments, when viewed as a cross-section of the transistor 1640 along the source-channel-drain direction, the gate electrode may consist of a U-shaped structure that includes a bottom portion substantially parallel to the surface of the die substrate 1602 and two sidewall portions that are substantially perpendicular to the top surface of the die substrate 1602. In other embodiments, at least one of the metal layers that form the gate electrode may simply be a planar layer that is substantially parallel to the top surface of the die substrate 1602 and does not include sidewall portions substantially perpendicular to the top surface of the die substrate 1602. In other embodiments, the gate electrode may consist of a combination of U-shaped structures and planar, non-U-shaped structures. For example, the gate electrode may consist of one or more U-shaped metal layers formed atop one or more planar, non-U-shaped layers.

In some embodiments, a pair of sidewall spacers may be formed on opposing sides of the gate stack to bracket the gate stack. The sidewall spacers may be formed from materials such as silicon nitride, silicon oxide, silicon carbide, silicon nitride doped with carbon, and silicon oxynitride. Processes for forming sidewall spacers are well known in the art and generally include deposition and etching process steps. In some embodiments, a plurality of spacer pairs may be used; for instance, two pairs, three pairs, or four pairs of sidewall spacers may be formed on opposing sides of the gate stack.

The S/D regions 1620 may be formed within the die substrate 1602 adjacent to the gate 1622 of each transistor 1640. The S/D regions 1620 may be formed using an implantation/diffusion process or an etching/deposition process, for example. In the former process, dopants such as boron, aluminum, antimony, phosphorous, or arsenic may be ion-implanted into the die substrate 1602 to form the S/D regions 1620. An annealing process that activates the dopants and causes them to diffuse farther into the die substrate 1602 may follow the ion-implantation process. In the latter process, the die substrate 1602 may first be etched to form recesses at the locations of the S/D regions 1620. An epitaxial deposition process may then be carried out to fill the recesses with material that is used to fabricate the S/D regions 1620. In some implementations, the S/D regions 1620 may be fabricated using a silicon alloy such as silicon germanium or silicon carbide. In some embodiments, the epitaxially deposited silicon alloy may be doped in situ with dopants such as boron, arsenic, or phosphorous. In some embodiments, the S/D regions 1620 may be formed using one or more alternate semiconductor materials such as germanium or a group III-V material or alloy. In further embodiments, one or more layers of metal and/or metal alloys may be used to form the S/D regions 1620.

Electrical signals, such as power and/or input/output (I/O) signals, may be routed to and/or from the devices (e.g., transistors 1640) of the device layer 1604 through one or more interconnect layers disposed on the device layer 1604 (illustrated in FIG. 9 as interconnect layers 1606-1610). For example, electrically conductive features of the device layer 1604 (e.g., the gate 1622 and the S/D contacts 1624) may be electrically coupled with the interconnect structures 1628 of the interconnect layers 1606-1610. The one or more interconnect layers 1606-1610 may form a metallization stack (also referred to as an “ILD stack”) 1619 of the IC device 1600.

The interconnect structures 1628 may be arranged within the interconnect layers 1606-1610 to route electrical signals according to a wide variety of designs; in particular, the arrangement is not limited to the particular configuration of interconnect structures 1628 depicted in FIG. 9. Although a particular number of interconnect layers 1606-1610 is depicted in FIG. 9, embodiments of the present disclosure include IC devices having more or fewer interconnect layers than depicted.

In some embodiments, the interconnect structures 1628 may include lines 1628 a and/or vias 1628 b filled with an electrically conductive material such as a metal. The lines 1628 a may be arranged to route electrical signals in a direction of a plane that is substantially parallel with a surface of the die substrate 1602 upon which the device layer 1604 is formed. For example, the lines 1628 a may route electrical signals in a direction in and out of the page from the perspective of FIG. 9. The vias 1628 b may be arranged to route electrical signals in a direction of a plane that is substantially perpendicular to the surface of the die substrate 1602 upon which the device layer 1604 is formed. In some embodiments, the vias 1628 b may electrically couple lines 1628 a of different interconnect layers 1606-1610 together.

The interconnect layers 1606-1610 may include a dielectric material 1626 disposed between the interconnect structures 1628, as shown in FIG. 9. In some embodiments, the dielectric material 1626 disposed between the interconnect structures 1628 in different ones of the interconnect layers 1606-1610 may have different compositions; in other embodiments, the composition of the dielectric material 1626 between different interconnect layers 1606-1610 may be the same.

A first interconnect layer 1606 (referred to as Metal 1 or “M1”) may be formed directly on the device layer 1604. In some embodiments, the first interconnect layer 1606 may include lines 1628 a and/or vias 1628 b, as shown. The lines 1628 a of the first interconnect layer 1606 may be coupled with contacts (e.g., the S/D contacts 1624) of the device layer 1604.

A second interconnect layer 1608 (referred to as Metal 2 or “M2”) may be formed directly on the first interconnect layer 1606. In some embodiments, the second interconnect layer 1608 may include vias 1628 b to couple the lines 1628 a of the second interconnect layer 1608 with the lines 1628 a of the first interconnect layer 1606. Although the lines 1628 a and the vias 1628 b are structurally delineated with a line within each interconnect layer (e.g., within the second interconnect layer 1608) for the sake of clarity, the lines 1628 a and the vias 1628 b may be structurally and/or materially contiguous (e.g., simultaneously filled during a dual damascene process) in some embodiments.

A third interconnect layer 1610 (referred to as Metal 3 or “M3”) (and additional interconnect layers, as desired) may be formed in succession on the second interconnect layer 1608 according to similar techniques and configurations described in connection with the second interconnect layer 1608 or the first interconnect layer 1606. In some embodiments, the interconnect layers that are “higher up” in the metallization stack 1619 in the IC device 1600 (i.e., farther away from the device layer 1604) may be thicker.

The IC device 1600 may include a solder resist material 1634 (e.g., polyimide or similar material) and one or more conductive contacts 1636 formed on the interconnect layers 1606-1610. In FIG. 9, the conductive contacts 1636 are illustrated as taking the form of bond pads. The conductive contacts 1636 may be electrically coupled with the interconnect structures 1628 and configured to route the electrical signals of the transistor(s) 1640 to other external devices. For example, solder bonds may be formed on the one or more conductive contacts 1636 to mechanically and/or electrically couple a chip including the IC device 1600 with another component (e.g., a circuit board). The IC device 1600 may include additional or alternate structures to route the electrical signals from the interconnect layers 1606-1610; for example, the conductive contacts 1636 may include other analogous features (e.g., posts) that route the electrical signals to external components. The conductive contacts 1636 may serve as the conductive contacts 122 or 124, as appropriate.

In some embodiments in which the IC device 1600 is a double-sided die (e.g., like the die 114-1), the IC device 1600 may include another metallization stack (not shown) on the opposite side of the device layer(s) 1604. This metallization stack may include multiple interconnect layers as discussed above with reference to the interconnect layers 1606-1610, to provide conductive pathways (e.g., including conductive lines and vias) between the device layer(s) 1604 and additional conductive contacts (not shown) on the opposite side of the IC device 1600 from the conductive contacts 1636. These additional conductive contacts may serve as the conductive contacts 122 or 124, as appropriate.

In other embodiments in which the IC device 1600 is a double-sided die (e.g., like the die 114-1), the IC device 1600 may include one or more TSVs through the die substrate 1602; these TSVs may make contact with the device layer(s) 1604, and may provide conductive pathways between the device layer(s) 1604 and additional conductive contacts (not shown) on the opposite side of the IC device 1600 from the conductive contacts 1636. These additional conductive contacts may serve as the conductive contacts 122 or 124, as appropriate.

FIG. 10 is a cross-sectional side view of an IC device assembly 1700 that may include any of the microelectronic assemblies 100 disclosed herein. In some embodiments, the IC device assembly 1700 may be a microelectronic assembly 100. The IC device assembly 1700 includes a number of components disposed on a circuit board 1702 (which may be, e.g., a motherboard). The IC device assembly 1700 includes components disposed on a first face 1740 of the circuit board 1702 and an opposing second face 1742 of the circuit board 1702; generally, components may be disposed on one or both faces 1740 and 1742. Any of the IC packages discussed below with reference to the IC device assembly 1700 may take the form of any suitable ones of the embodiments of the microelectronic assemblies 100 disclosed herein.

In some embodiments, the circuit board 1702 may be a PCB including multiple metal layers separated from one another by layers of dielectric material and interconnected by electrically conductive vias. Any one or more of the metal layers may be formed in a desired circuit pattern to route electrical signals (optionally in conjunction with other metal layers) between the components coupled to the circuit board 1702. In other embodiments, the circuit board 1702 may be a non-PCB substrate. In some embodiments the circuit board 1702 may be, for example, a circuit board.

The IC device assembly 1700 illustrated in FIG. 10 includes a package-on-interposer structure 1736 coupled to the first face 1740 of the circuit board 1702 by coupling components 1716. The coupling components 1716 may electrically and mechanically couple the package-on-interposer structure 1736 to the circuit board 1702, and may include solder balls (as shown in FIG. 10), male and female portions of a socket, an adhesive, an underfill material, and/or any other suitable electrical and/or mechanical coupling structure.

The package-on-interposer structure 1736 may include an IC package 1720 coupled to an interposer 1704 by coupling components 1718. The coupling components 1718 may take any suitable form for the application, such as the forms discussed above with reference to the coupling components 1716. Although a single IC package 1720 is shown in FIG. 10, multiple IC packages may be coupled to the interposer 1704; indeed, additional interposers may be coupled to the interposer 1704. The interposer 1704 may provide an intervening substrate used to bridge the circuit board 1702 and the IC package 1720. The IC package 1720 may be or include, for example, a die (the die 1502 of FIG. 8), an IC device (e.g., the IC device 1600 of FIG. 9), or any other suitable component. Generally, the interposer 1704 may spread a connection to a wider pitch or reroute a connection to a different connection. For example, the interposer 1704 may couple the IC package 1720 (e.g., a die) to a set of ball grid array (BGA) conductive contacts of the coupling components 1716 for coupling to the circuit board 1702. In the embodiment illustrated in FIG. 10, the IC package 1720 and the circuit board 1702 are attached to opposing sides of the interposer 1704; in other embodiments, the IC package 1720 and the circuit board 1702 may be attached to a same side of the interposer 1704. In some embodiments, three or more components may be interconnected by way of the interposer 1704.

In some embodiments, the interposer 1704 may be formed as a PCB, including multiple metal layers separated from one another by layers of dielectric material and interconnected by electrically conductive vias. In some embodiments, the interposer 1704 may be formed of an epoxy resin, a fiberglass-reinforced epoxy resin, an epoxy resin with inorganic fillers, a ceramic material, or a polymer material such as polyimide. In some embodiments, the interposer 1704 may be formed of alternate rigid or flexible materials that may include the same materials described above for use in a semiconductor substrate, such as silicon, germanium, and other group III-V and group IV materials. The interposer 1704 may include metal interconnects 1708 and vias 1710, including but not limited to TSVs 1706. The interposer 1704 may further include embedded devices 1714, including both passive and active devices. Such devices may include, but are not limited to, capacitors, decoupling capacitors, resistors, inductors, fuses, diodes, transformers, sensors, electrostatic discharge (ESD) devices, and memory devices. More complex devices such as radio frequency devices, power amplifiers, power management devices, antennas, arrays, sensors, and microelectromechanical systems (MEMS) devices may also be formed on the interposer 1704. The package-on-interposer structure 1736 may take the form of any of the package-on-interposer structures known in the art.

The IC device assembly 1700 may include an IC package 1724 coupled to the first face 1740 of the circuit board 1702 by coupling components 1722. The coupling components 1722 may take the form of any of the embodiments discussed above with reference to the coupling components 1716, and the IC package 1724 may take the form of any of the embodiments discussed above with reference to the IC package 1720.

The IC device assembly 1700 illustrated in FIG. 10 includes a package-on-package structure 1734 coupled to the second face 1742 of the circuit board 1702 by coupling components 1728. The package-on-package structure 1734 may include an IC package 1726 and an IC package 1732 coupled together by coupling components 1730 such that the IC package 1726 is disposed between the circuit board 1702 and the IC package 1732. The coupling components 1728 and 1730 may take the form of any of the embodiments of the coupling components 1716 discussed above, and the IC packages 1726 and 1732 may take the form of any of the embodiments of the IC package 1720 discussed above. The package-on-package structure 1734 may be configured in accordance with any of the package-on-package structures known in the art.

FIG. 11 is a block diagram of an example electrical device 1800 that may include one or more of the microelectronic assemblies 100 disclosed herein. For example, any suitable ones of the components of the electrical device 1800 may include one or more of the IC device assemblies 1700, IC devices 1600, or dies 1502 disclosed herein, and may be arranged in any of the microelectronic assemblies 100 disclosed herein. A number of components are illustrated in FIG. 11 as included in the electrical device 1800, but any one or more of these components may be omitted or duplicated, as suitable for the application. In some embodiments, some or all of the components included in the electrical device 1800 may be attached to one or more motherboards. In some embodiments, some or all of these components are fabricated onto a single system-on-a-chip (SoC) die.

Additionally, in various embodiments, the electrical device 1800 may not include one or more of the components illustrated in FIG. 11, but the electrical device 1800 may include interface circuitry for coupling to the one or more components. For example, the electrical device 1800 may not include a display device 1806, but may include display device interface circuitry (e.g., a connector and driver circuitry) to which a display device 1806 may be coupled. In another set of examples, the electrical device 1800 may not include an audio input device 1824 or an audio output device 1808, but may include audio input or output device interface circuitry (e.g., connectors and supporting circuitry) to which an audio input device 1824 or audio output device 1808 may be coupled.

The electrical device 1800 may include a processing device 1802 (e.g., one or more processing devices). As used herein, the term “processing device” or “processor” may refer to any device or portion of a device that processes electronic data from registers and/or memory to transform that electronic data into other electronic data that may be stored in registers and/or memory. The processing device 1802 may include one or more digital signal processors (DSPs), application-specific ICs (ASICs), central processing units (CPUs), graphics processing units (GPUs), cryptoprocessors (specialized processors that execute cryptographic algorithms within hardware), server processors, or any other suitable processing devices. The electrical device 1800 may include a memory 1804, which may itself include one or more memory devices such as volatile memory (e.g., dynamic RAM (DRAM)), nonvolatile memory (e.g., read-only memory (ROM)), flash memory, solid state memory, and/or a hard drive. In some embodiments, the memory 1804 may include memory that shares a die with the processing device 1802. This memory may be used as cache memory and may include embedded dynamic RAM (eDRAM) or spin transfer torque magnetic RAM (STT-M RAM).

In some embodiments, the electrical device 1800 may include a communication chip 1812 (e.g., one or more communication chips). For example, the communication chip 1812 may be configured for managing wireless communications for the transfer of data to and from the electrical device 1800. The term “wireless” and its derivatives may be used to describe circuits, devices, systems, methods, techniques, communications channels, etc., that may communicate data through the use of modulated electromagnetic radiation through a nonsolid medium. The term does not imply that the associated devices do not contain any wires, although in some embodiments they might not.

The communication chip 1812 may implement any of a number of wireless standards or protocols, including but not limited to Institute for Electrical and Electronic Engineers (IEEE) standards including Wi-Fi (IEEE 802.11 family), IEEE 802.16 standards (e.g., IEEE 802.16-2005 Amendment), Long-Term Evolution (LTE) project along with any amendments, updates, and/or revisions (e.g., advanced LTE project, ultra mobile broadband (UMB) project (also referred to as “3GPP2”), etc.). IEEE 802.16 compatible Broadband Wireless Access (BWA) networks are generally referred to as WiMAX networks, an acronym that stands for Worldwide Interoperability for Microwave Access, which is a certification mark for products that pass conformity and interoperability tests for the IEEE 802.16 standards. The communication chip 1812 may operate in accordance with a Global System for Mobile Communication (GSM), General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UMLS), High Speed Packet Access (HSPA), Evolved HSPA (E-HSPA), or LTE network. The communication chip 1812 may operate in accordance with Enhanced Data for GSM Evolution (EDGE), GSM EDGE Radio Access Network (GERAN), Universal Terrestrial Radio Access Network (UTRAN), or Evolved UTRAN (E-UTRAN). The communication chip 1812 may operate in accordance with Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Digital Enhanced Cordless Telecommunications (DECT), Evolution-Data Optimized (EV-DO), and derivatives thereof, as well as any other wireless protocols that are designated as 3G, 4G, 5G, and beyond. The communication chip 1812 may operate in accordance with other wireless protocols in other embodiments. The electrical device 1800 may include an antenna 1822 to facilitate wireless communications and/or to receive other wireless communications (such as AM or FM radio transmissions).

In some embodiments, the communication chip 1812 may manage wired communications, such as electrical, optical, or any other suitable communication protocols (e.g., the Ethernet). As noted above, the communication chip 1812 may include multiple communication chips. For instance, a first communication chip 1812 may be dedicated to shorter-range wireless communications such as Wi-Fi or Bluetooth, and a second communication chip 1812 may be dedicated to longer-range wireless communications such as global positioning system (GPS), EDGE, GPRS, CDMA, WiMAX, LTE, EV-DO, or others. In some embodiments, a first communication chip 1812 may be dedicated to wireless communications, and a second communication chip 1812 may be dedicated to wired communications.

The electrical device 1800 may include battery/power circuitry 1814. The battery/power circuitry 1814 may include one or more energy storage devices (e.g., batteries or capacitors) and/or circuitry for coupling components of the electrical device 1800 to an energy source separate from the electrical device 1800 (e.g., AC line power).

The electrical device 1800 may include a display device 1806 (or corresponding interface circuitry, as discussed above). The display device 1806 may include any visual indicators, such as a heads-up display, a computer monitor, a projector, a touchscreen display, a liquid crystal display (LCD), a light-emitting diode display, or a flat panel display.

The electrical device 1800 may include an audio output device 1808 (or corresponding interface circuitry, as discussed above). The audio output device 1808 may include any device that generates an audible indicator, such as speakers, headsets, or earbuds.

The electrical device 1800 may include an audio input device 1824 (or corresponding interface circuitry, as discussed above). The audio input device 1824 may include any device that generates a signal representative of a sound, such as microphones, microphone arrays, or digital instruments (e.g., instruments having a musical instrument digital interface (MIDI) output).

The electrical device 1800 may include a GPS device 1818 (or corresponding interface circuitry, as discussed above). The GPS device 1818 may be in communication with a satellite-based system and may receive a location of the electrical device 1800, as known in the art.

The electrical device 1800 may include an other output device 1810 (or corresponding interface circuitry, as discussed above). Examples of the other output device 1810 may include an audio codec, a video codec, a printer, a wired or wireless transmitter for providing information to other devices, or an additional storage device.

The electrical device 1800 may include an other input device 1820 (or corresponding interface circuitry, as discussed above). Examples of the other input device 1820 may include an accelerometer, a gyroscope, a compass, an image capture device, a keyboard, a cursor control device such as a mouse, a stylus, a touchpad, a bar code reader, a Quick Response (QR) code reader, any sensor, or a radio frequency identification (RFID) reader.

The electrical device 1800 may have any desired form factor, such as a computing device or a hand-held, portable or mobile computing device (e.g., a cell phone, a smart phone, a mobile internet device, a music player, a tablet computer, a laptop computer, a netbook computer, an ultrabook computer, a personal digital assistant (PDA), an ultra mobile personal computer, etc.), a desktop electrical device, a server, or other networked computing component, a printer, a scanner, a monitor, a set-top box, an entertainment control unit, a vehicle control unit, a digital camera, a digital video recorder, or a wearable computing device. In some embodiments, the electrical device 1800 may be any other electronic device that processes data.

The following paragraphs provide various examples of the embodiments disclosed herein.

Example 1 is a microelectronic assembly, including: a first die having a first surface and an opposing second surface in a first dielectric layer; a magnetic core inductor, having a first surface and an opposing second surface, in the first dielectric layer, wherein the magnetic core inductor includes: a first conductive pillar at least partially surrounded by a magnetic material; and a second conductive pillar coupled to the first conductive pillar; and a second die having a first surface and an opposing second surface, in a second dielectric layer, wherein the second dielectric layer is on the first dielectric layer, and wherein the first surface of the second die is coupled to the second surface of the magnetic core inductor.

Example 2 may include the subject matter of Example 1, and may further specify that the second conductive pillar of the magnetic core inductor is at least partially surrounded by the magnetic material.

Example 3 may include the subject matter of Example 1, and may further specify that the second conductive pillar is coupled to the first conductive pillar at the first surface of the magnetic core inductor.

Example 4 may include the subject matter of Example 1, and may further specify that the first surface of the magnetic core inductor is coupled to a package substrate.

Example 5 may include the subject matter of Example 4, and may further specify that the second conductive pillar is coupled to the first conductive pillar via a conductive pathway in the package substrate.

Example 6 may include the subject matter of Example 1, and may further specify that the first conductive pillar and the second conductive pillar are embedded in a magnetic material.

Example 7 may include the subject matter of Example 6, and may further specify that the magnetic material comprises one or more of: iron, nickel, cobalt, ferrite, a Heusler alloy, a permalloy, a Mu metal, a cobalt-zirconium-tantalum alloy, and a dielectric with magnetic particles or flakes.

Example 8 is a microelectronic assembly, including: a magnetic core inductor having a first surface and an opposing second surface in a first dielectric layer, wherein the magnetic core inductor includes a first conductive pillar at least partially surrounded by a magnetic material and a second conductive pillar coupled to the first conductive pillar; and a die having a first surface and an opposing second surface in a second dielectric layer, wherein the second dielectric layer is on the first dielectric layer, and wherein the first surface of the die is coupled to the second surface of the magnetic core inductor.

Example 9 may include the subject matter of Example 8, and may further specify that the second conductive pillar is coupled to the first conductive pillar at the first surface of the magnetic core inductor.

Example 10 may include the subject matter of Example 8, and may further include: a package substrate, and wherein the first surface of the magnetic core inductor is coupled to the package substrate.

Example 11 may include the subject matter of Example 10, and may further specify that the second conductive pillar is coupled to the first conductive pillar via a conductive pathway in the package substrate.

Example 12 may include the subject matter of Example 8, and may further specify that the magnetic material comprises one or more of: iron, nickel, cobalt, ferrite, a Heusler alloy, a permalloy, a Mu metal, a cobalt-zirconium-tantalum alloy, and a dielectric with magnetic particles or flakes.

Example 13 may include the subject matter of Example 8, and may further include: a redistribution layer at the first surface of the magnetic core inductor.

Example 14 may include the subject matter of Example 8, and may further include: a redistribution layer at the second surface of the magnetic core inductor.

Example 15 may include the subject matter of Example 8, and may further specify that a height of the first conductive pillar is between 50 microns and 500 microns.

Example 16 may include the subject matter of Example 8, and may further specify that the first conductive pillar includes copper.

Example 17 is a method of manufacturing a microelectronic assembly, including: forming a first conductive pillar in a first dielectric layer having a first surface and an opposing second surface; forming a second conductive pillar in the first dielectric layer having a first surface and an opposing second surface; forming a magnetic material at least partially around the first conductive pillar; forming a first interconnect between the first conductive pillar and a die at the second surface; forming a second interconnect between the second conductive pillar and the die at the second surface; and forming a conductive pathway between the first surface of the first conductive pillar and the first surface of the second conductive pillar.

Example 18 may include the subject matter of Example 17, and may further specify that the conductive pathway is in a package substrate.

Example 19 may include the subject matter of Example 17, and may further include: embedding the die in a second dielectric layer.

Example 20 may include the subject matter of Example 17, and may further include: forming a redistribution layer at the first surface of the first and second conductive pillars, wherein the conductive pathway between the first surface of the first conductive pillar and the first surface of the second conductive pillar is in the redistribution layer.

Example 21 is a computing device, including: a package substrate having a first surface and an opposing second surface; a first die having a first surface and an opposing second surface in a first dielectric layer, and wherein the first surface of the first die is coupled to the second surface of the package substrate; an inductor having a first surface and an opposing second surface, wherein the inductor is in the first dielectric layer, wherein the inductor includes a first conductive pillar and a second conductive pillar coupled to the first conductive pillar, and wherein the first conductive pillar and the second conductive pillar are at least partially surrounded by a magnetic material; and a second die having a first surface and an opposing second surface in a second dielectric layer, wherein the second dielectric layer is on the first dielectric layer, and wherein the first surface of the second die is coupled to the second surface of the inductor and to the second surface of the first die.

Example 22 may include the subject matter of Example 21, and may further specify that the first surface of the inductor is coupled to the second surface of the package substrate.

Example 23 may include the subject matter of Example 21, and may further specify that the first conductive pillar and the second conductive pillar are embedded in the magnetic material.

Example 24 may include the subject matter of Example 21, and may further specify that the second conductive pillar is coupled to the first conductive pillar at the first surface of the inductor.

Example 25 may include the subject matter of Example 21, and may further specify that the second conductive pillar is coupled to the first conductive pillar via a conductive pathway in the package substrate.

Example 26 may include the subject matter of Example 21, and may further include: a redistribution layer at the first surface of the inductor.

Example 27 may include the subject matter of Example 21, and may further include: a redistribution layer at the second surface of the inductor.

Example 28 may include the subject matter of Example 21, and may further specify that the inductor further comprises: a third conductive pillar coupled to the second conductive pillar; and a fourth conductive pillar coupled to the third conductive pillar.

Example 29 may include the subject matter of Example 28, and may further specify that third conductive pillar is electrically coupled to the second conductive pillar at the second surface of the inductor and the fourth conductive pillar is electrically coupled to the third conductive pillar at the first surface of the inductor.

Example 30 may include the subject matter of Example 21, and may further specify that the first die or the second die is a central processing unit, a radio frequency chip, a power converter, or a network processor.

Example 31 may include the subject matter of Example 21, furthering comprising: a circuit board, wherein the first surface of the package substrate is coupled to a surface of the circuit board.

Example 32 may include the subject matter of Example 21, and may further specify that the computing device is a server.

Example 33 may include the subject matter of Example 21, and may further specify that the computing device is a portable computing device.

Example 34 may include the subject matter of Example 21, and may further specify that the computing device is a wearable computing device.

Example 35 may include the subject matter of Example 21, and may further specify that the package substrate is a printed circuit board.

Example 36 may include the subject matter of Example 21, and may further specify that a pitch of the first conductive pillar and the second conductive pillar is between 50 microns and 500 microns.

Example 37 may include the subject matter of Example 21, may further specify that the inductor is a first inductor, and may further include: a second inductor having a first surface and an opposing second surface, wherein the second inductor is in the first dielectric layer, wherein the second inductor includes a first conductive pillar and a second conductive pillar coupled to the first conductive pillar, and wherein the first conductive pillar and the second conductive pillar are at least partially surrounded by a magnetic material.

Example 38 may include the subject matter of Example 37, and may further specify that a distance between the second conductive pillar of the first inductor and the first conductive pillar of the second inductor is between 50 microns and 2000 microns. 

The invention claimed is:
 1. A microelectronic assembly, comprising: a first die having a first surface and an opposing second surface in a first dielectric layer; a magnetic core inductor, having a first surface and an opposing second surface, in the first dielectric layer, wherein the magnetic core inductor includes: a first conductive pillar at least partially surrounded by a magnetic material, wherein a height of the first conductive pillar is between 50 microns and 500 microns; and a second conductive pillar coupled to the first conductive pillar; and a second die having a first surface and an opposing second surface, in a second dielectric layer, wherein the second dielectric layer is on the first dielectric layer, and wherein the first surface of the second die is coupled to the second surface of the magnetic core inductor.
 2. The microelectronic assembly of claim 1, wherein the second conductive pillar of the magnetic core inductor is at least partially surrounded by the magnetic material.
 3. The microelectronic assembly of claim 1, wherein the second conductive pillar is coupled to the first conductive pillar at the first surface of the magnetic core inductor.
 4. The microelectronic assembly of claim 1, wherein the first surface of the magnetic core inductor is coupled to a package substrate.
 5. The microelectronic assembly of claim 4, wherein the second conductive pillar is coupled to the first conductive pillar via a conductive pathway in the package substrate.
 6. The microelectronic assembly of claim 1, wherein the first conductive pillar and the second conductive pillar are embedded in a magnetic material.
 7. The microelectronic assembly of claim 6, wherein the magnetic material comprises one or more of: iron, nickel, cobalt, ferrite, a Heusler alloy, a permalloy, a Mu metal, a cobalt-zirconium-tantalum alloy, and a dielectric with magnetic particles or flakes.
 8. A microelectronic assembly, comprising: a magnetic core inductor having a first surface and an opposing second surface in a first dielectric layer, wherein the magnetic core inductor includes a first conductive pillar at least partially surrounded by a magnetic material and a second conductive pillar coupled to the first conductive pillar, wherein a height of the first conductive pillar is between 50 microns and 500 microns; and a die having a first surface and an opposing second surface in a second dielectric layer, wherein the second dielectric layer is on the first dielectric layer, and wherein the first surface of the die is coupled to the second surface of the magnetic core inductor.
 9. The microelectronic assembly of claim 8, wherein the second conductive pillar is coupled to the first conductive pillar at the first surface of the magnetic core inductor.
 10. The microelectronic assembly of claim 8, further comprising: a package substrate, and wherein the first surface of the magnetic core inductor is coupled to the package substrate.
 11. The microelectronic assembly of claim 10, wherein the second conductive pillar is coupled to the first conductive pillar via a conductive pathway in the package substrate.
 12. The microelectronic assembly of claim 8, wherein the magnetic material comprises one or more of: iron, nickel, cobalt, ferrite, a Heusler alloy, a permalloy, a Mu metal, a cobalt-zirconium-tantalum alloy, and a dielectric with magnetic particles or flakes.
 13. The microelectronic assembly of claim 8, further comprising: a redistribution layer at the first surface of the magnetic core inductor.
 14. The microelectronic assembly of claim 8, further comprising: a redistribution layer at the second surface of the magnetic core inductor.
 15. The microelectronic assembly of claim 8, wherein the first conductive pillar includes copper.
 16. A method of manufacturing a microelectronic assembly, comprising: forming a first conductive pillar in a first dielectric layer having a first surface and an opposing second surface; forming a second conductive pillar in the first dielectric layer having a first surface and an opposing second surface; forming a magnetic material at least partially around the first conductive pillar; forming a first interconnect between the first conductive pillar and a die at the second surface; forming a second interconnect between the second conductive pillar and the die at the second surface; and forming a conductive pathway between the first surface of the first conductive pillar and the first surface of the second conductive pillar.
 17. The method of claim 16, wherein the conductive pathway is in a package substrate.
 18. The method of claim 16, further comprising: embedding the die in a second dielectric layer.
 19. The method of claim 16, further comprising: forming a redistribution layer at the first surface of the first and second conductive pillars, wherein the conductive pathway between the first surface of the first conductive pillar and the first surface of the second conductive pillar is in the redistribution layer. 